The development of internalizing problems in early childhood: The importance of sibling clustering.

Within family sibling clustering of internalizing problems is examined during the early childhood period. Sibling clustering, the ongoing sibling similarity in internalizing problems, may be a result of heritability of internalizing problems, as well as shared environmental effects. Clustering may also result from the time-varying influence of sibling socialization, where 1 sibling is teaching or modeling internalizing problems to the other...